Method of and means for producing composite metal products



T. B. CHACE April 2, 1940.

METHOD OF AND BEANS FOR PRODUCING COIPOSITE IETAL PRODUCTS Filfld Feb.7. 1938 Patented Apr. 2, 1940 UNITED fsTA'r-Es PATEN METHOD or ANDmonsoon PRODUCING comosrrnrm'ru. rnonuc'rs Thomas B. clm'o, Winnetka,n1.

Application February 7,

1938; Serial. No. 189397 isclaims. (c1. ea -203),, J"

part of my copending applications, Serial No.

6,497,filed' February 14, 1935, now Patent-2,35,- 248, and Serial No.64,280, filed February 17, 1936. In the bonding to steel of some highcorrosion v resistant alloys and the 'subsequentrolling of the compositeslab, the design'and type of mould is I very important in' m'akingtheprocess commercial and the prOduct-usabIeL -Some of *the copjieralloys, such as silicon copper,- are" particularly fluid inthe moltenstate and are very diilicult to hold, in the-molten state,onrthe-surface of the f steel backing slab. Some oftheothernon-corrosive alloys, such asthe highni'ckel coppers of from 20%to 40% nickel content, having melting tempe'raturta'sup to 2400 FL, orMonel metaltor stainless steeLhavingmelting temperatures similar to thesteel backing? slab; are diflicultto hold in the molten statebecause orthe extremely high casting temperaturesinvolyedi The mould must beliquid-tight after having-beenfpreheated to k temperaturesofaround'2200"'F. I Large slabs having a thickness'of l0'-"fto 12" must bepreheatedfor fiveor sikhours at; this temperature, 'an'dfl'themouldiorm'in'g a part thereof mustf'b'e such thaf-it not out and willremain liquid-tighh'as a containeriorj I the molten 'flux duringthepreheating, as well as 5 a contai ner forthe"vnon=corrosivefmetalwliicli is cast in the mould after preheating fcasting operation diil'ersf roiii ordinary casting in T V that themould; in some'fcases', is preheated to a n e eabbv the m n he of mi nca 40 ins loy and,

me, new .fbrgj' nel mould o metal solidifies quickly: In'Iact; forjthe.cladding hot rolling temperaturew exposed while the mouldis beingnlle'the cladding metal is'-f;reezing.x-z-s v i 'Aiiotherobj'e'ct' oimyiiiiventi'on'is to open-faced mould-formedt'by a slab of: base metal.16

-' obviousandin partappeamhereinafter; V iacc'ordinglynmy invention'is'dis'closed in the d ramrigyand troom backing l z lq gl p gwmdescriptionhereinafter set-forth-and the scope 1 steel slab, theheatjsmaintained-for a considerl 3 able period and the cast metal remains][molten I v. much longer than ordinaryscastmetal rema-ins '5 moltene ina cold: mould; m which case -the-. cast metal nos solidified'and cooledto the maximum Another object o: my invention is to provide anopen-facewmomd .on which the depth andwidth can be readily regulated asthe measuring means I 'for determining the: required thickness ofthe-cast "alloy-in proportion ,to the steelbacking metal.

Another object. of my inventionis to providez an open facedmould'thatcan bowed to cladna; relatively large surface Iof a slab of :ba'sezmetaland ,10

1 to leave only a. 'sm-all'surface of the cladding metal and whenprovideian and a thin metal mould member,- which mould liquid tightandsuch that'the' mould fllling metal will not bond to Ithe thin "metalmould member. p v I Another object of my invention is to provide 2o-'-open-faced' mould by means or which a slab of base" metal can -.be'icladded on; oppositesurfaces with different cladding metals, suchaswapcopper Jalloy"on one surface and nickel or stainless-steelentheothrsurfacaz r 25 -"A further object of my invention-As towprovidean fopen-facedi mould a construction; that can be 'readily adapted tofit any size ofslablorwb'a'cking material; v -Another objectiof myinvention': is to provide an Other-'objectS-"of inwihveiitiomwill, inart be ses": the Ieatu'resTjof o'onelements aricl arrange- '11 beexemplified iii-the v s'truction; combination montnorx grts whioh 4owill be" indicated in not some combinations,'-such.or example as mysilicon-copper alloys,':'it is n'ecessary to prolong* the molten'stat'eof the casting alloy tofperfect-a a:

b o'nd between mem s o r I In few oi the'iforegoing, an object o'f'myiinven- J m s t e Prov des; 0 1a; mo ,w f a be a. rol e t'q ab/J1me;ly from the'bonding heat or as soonas the cast" "Figure '2 is. asectional view tokori along ftfie line 2-2 of Figure 1;

1 3 a1 vimE= Li I it t? h sb View of another mould construction forproducing a com:

- mould for the purpose of cladding by castingone posite slab having alayer of cladding metal on the top and end surfaces;

Figure 4 is a sectional view taken along the line 44 of Figure 3; and

Figure 5 is a sectional view showing one form of mould construction forproducing a slab with a layer of cladding metal on a large lateralsurface and the bottom of the mould being closed by resting the mouldconstruction on a foundry floor.

The utility and construction of my type of metal or different metals onopposite surfaces of another, or on the upper surface in combinationwith other surfaces, are of great importance. For instance, any size ofslab or backing member may be chosen with respect to starting and finished size which best fits the requirements of a particular order orspecification with a minimum scrap loss. This permits using regularbloom sections requiring a minimum of processing before cladding. If theclad slab is to be rolled into plates, for instance, and if the facingorcasting alloy has similar compression resistance to the steel backingmaterial so that they roll'evenly. the steel strips and channel-shapedmembers are welded to the sides and ends, leaving the full area oftheslab for cladding, thus producing a minimum of scrap loss. If thebloom has irregular edges and ends, so that welding along the edges andends is not practical, the mould members can be located on the upper'andside surfacesof the bloom, leaving the irregular ends and edgesextending on the outside-of the mould members. It will be understoodthat the different conditions will govern the particular type of mouldconstruction that is employed.

' There are some cases in which it is desirable to clad a base metalslab on opposite surfaces with different metals. In the application ofcladded metal to heat exchangers, condenser tubes and other industrialuses, the cladded metal may be exposed to a different condition on onesurface than it is on the other. Hence it is desirable to clad theopposite surfaces with metals or alloys suitable to the'conditions \mderwhich they are to be used. In some cases it might be desirable to have acopper alloy on one surface and stainless steel or a nickel alloy on theother. Mould constructions and methods are described hereinafter whichcan be used to clad a slab of base metal on opposite surfaces with thesame or different metals.

Referring to Figures 1 and 2, there is shown a mould construction bywhich opposite surfaces of a slab may be clad. As therein illustrated, amould construction is provided for cladding the opposite surfaces Hand28 of aslab of base metal .29. For this purposerelatively thin metalmould members 30 are provided, having inturned end and sideportionsfland If that may be welded to the adjacent sides andaend ofthe-slab II,as indicated at and ,respectively. The mould spaces thus formed may befilled with a suitable flux and thenthe mould may be preheated to bringit up to the desired temperature. The mould spaces. may then be filledwith the desired cladding metal to provide, on cooling, as

I composite slab with integrally bo'ndedllayers of cladding metal on theopposite surfacq .21 and 28. The inturned bottoms ,Il may be omitted andthe mould construction be set on sand floor of the foundry so as toclose the bottom of the mouldspaces.

Themould construction 1 v v and 2 may .be lined .with anon-binding.material and used in the same manner as is the mould construction shownin Figure 5 and described hereinafter. This will allow the removal ofthe closed by inturned projections if as shown in Figure 1 but areclosed by a. sand floor, this will I allow the base metal slab to beheated in a molten bath of slag. When the slab is withdrawn, the

slag willrun out of the mould space and a thin coating of slag willadhere to the surface of the slab and to the surface of the mouldmembers ll, thereby preventing oxidation. When the mould is poured, thiscoating will fuseand be displaced by cladding metal. 7 V

In Figures 3 and 4 of the drawing a. mould construction is illustratedthat may be employed for. cladding the top surface 31 and end surfaces3! of a base metal slab as. For this purpose relativelythin side members40 are welded, as indicated at 4|, to the top surface 31 along itsedges. Relatively thin metal mould members 42, having inturned sides 43and bottoms ll, are spacedfrom the ,end surfaces II, as shown, and arewelded to the side and-bottom surfaces of the slab 39, as indicated atIf and 40. The inturned bottoms 44 may be omitted and the mould heatedup to the welding temperature.

For the purpose of definitely limiting the depth of cladding metal abovethe top surface 31, the mould members 42 may be provided with cut-away.sections 41 through which the molten elsglding metal may escape.

' Figure 5 a mould construction is illustratedwhichmaybeusedtocladalargesurface 4! of a base metal slab II. The bottomii of the mould is shown as being closed by a foundry floor If. Usingthe floor 52 to close the mould may, in some cases, be desirable ratherthan closing the mould by inturning a" projection on the base of themould member ll.

The inner surface 54 of mould member 3 is coated or lined with asuitable material it such .asa fl're clay or an aluminum oxide base toform a non-:bonding surface to be contacted by the cladding metal. Thisnon-bonding surface may be provided by oxidizing the inner surface- I4of the mould member I! so that-a scale will be formed thereupon. Theinner surface 84 may Thismaybe depositedbymeansofawash, like whitewash.Sodium silicate may be employed to attach a layer of powdered materialto the se- Bysocoatingorliningtbeinner 1 'member 53 after the claddingmetal has frozen,

as by cutting it away with a torch, and thus have a clean surface ofcladding metal exposed. If a suitable bond-preventing layer is provided,the slab may be rolled through a desired stage or stages without removalof the mould II.

The mould member 53 is substantially channel-shaped. It is welded on thebase metal slab on opposite sides in the same manner that mould members30 in Figures 1 and 2 are welded to the base metal slab 29 at 33. Thesand upon which it is set effectively seals the lower end of the mould.

The mould construction illustrated in Figure 5 has valuable advantagesin cladding a base metal slab with certain cladding metals. It isreadily seen from Figure 5 that only a small surface of the claddingmetal will be exposed when the metal is poured and after it solidifies.The small surface that is exposed will be on an end of the slab 50 andmay be cropped or cut off with little loss.

Some of the alloys and metals used for cladding are subject to rapidoxidation and gas absorption at the temperatures used for cladding.Certain metals, like copper, tend to squeeze out absorbed gases onfreezing, and form rough surfaces as a result. A small amount ofsilicon, as low as 0.1% or even less, tends to limit this gasabsorption. Using the mould construction as shown in Figure 5 thecladding metal may be subjected to high temperatures over long periods,and oxidation and gas absorption will be limited to the small surface onthe top of the mould. After the mould has cooled as much as desired themould member 53 may be removed and a clean and smooth surface ofcladding metal will be obtained.

Since certain further changes may be made in the foregoing mouldconstructions, and different embodiments of the invention may be madewithout departing from the scope thereof, it is intended that all mattershown in the accompanying drawing or described hereinbefore shall beinterpreted as illustrative and not in a limiting sense.

I claim as my invention:

. 1. Means for producing a composite slab comprising, a slab of basemetal of uniform thick ness, and a pair of relatively thin metal memberswelded to said slab on opposite sides in such manner as to form mouldsof substantiallyuniform width with adjacent surfaces of said slab forretaining cladding metal therein in the molten state whereby, oncooling, said slab is provided with integrally bonded layers of claddingmetal of substantially uniform thickness on said surfaces.

2. Means for producing a composite slab comprising, a slab of base metalof uniform thickness, and a pair of relatively thin metal channelshapedmembers welded to said slab on opposite sides in such manner as to formmoulds of substantiallyuniform width with adjacent surfaces of said slabfor retaining cladding metal therein in the molten state whereby, oncooling, said slab is provided with integrally bonded layers of claddingmetal of substantially uniform thickness on said surfacesr 3. Means forproducing a composite slab comprising, a slab of base metal of uniformthickness, and a pair of relatively thin metal channelshaped memberswelded to said slab on opposite vertical sides in such manner as to formmoulds of substantially uniform width with adiacent vertical surfaces ofsaid slab for retaining cladding metal therein in the molten statewhereby. on cooling, said slab is provided with integrally bonded layersof cladding metal of substantially uniform thickness on said surfaces,the lower ends of said channel-shaped members being turned inwardlytoward and welded to the bottom surface of said slab.

4. Means for producing a composite slab com prising, a slab of basemetal of uniform thickness, and a relatively thin metal member welded toopposite-sides of said slab so as to form a mould of substantiallyuniform width with the adjacent surface of said slab for retainingcladding metal therein in the molten state whereby, on cooling, saidslab is provided with an integrally bonded layer of cladding metal ofsubstantially uniformthickness on said surface.

5. Means for producing a composite slab comprising, a slab of base metalof uniform thickness, and a relatively thin metal channel-shaped memberwelded'to opposite sides of said slab so as to form a mould ofsubstantially uniform width with the adjacent surface of said slab forretaining cladding metal therein in the molten state whereby, oncooling, said slab is provided with an integrally bonded layer ofcladding metal of substantially uniform thickness on said surface.

6. Means for producing a composite slab comprising, a slab of base metalof uniform thickness, and a relatively thin metal channel-shaped memberwelded to said slab on opposite vertical sides in such manner as to forma mould of substantially uniform width with the adjacent verticalsurface of said slab for retaining cladding metal therein in the moltenstate whereby, on

cooling, said slab is provided with an integrally bonded layer ofcladding metal of substantially uniform thickness on said surface, thelower end of said channel-shaped member being turned inwardly toward andwelded to the bottom surface of said slab.

'7. Means for producing a composite slab comprising, a slab ofbasemetal, a pair of relatively thin metal and members welded to oppositesides of said slaband spaced from the end surfaces thereof, and a pairof relatively thin metal side members'welded along opposite sides ofsaid slab and projecting above the top surface thereof, said end andside members with the end and top surfaces of said slabforming a mouldfor retaining cladding metal therein in the molten state whereby, oncooling, saidslab is provided with an integrally bonded layer ofcladding metal on said end and top surfaces.

8. Means for producing a composite slab comprising, a slab of basemetal, a pair of relatively thin metal channel-shaped end members weldedto opposite side'jdf said slab and spaced from the and surfaces thereof,and a pair of relatively thin metal side members welded along oppositesides of said slab and projecting above the top surface thereof, saidand and side members with the end and top sin'faces of said slab forminga mould for retaining cladding metal therein in the molten statewhereby, on cooling, said slab is provided with an integrally bondedlayer of clad.- ding metal on said end and top surfaces.

9. Means for producing a composite slab compair of relatively. thinmetal side members welded along opposite vertical sides of said slab andprojecting above the top surface thereof,.said end and side members withthe end and top surfaces of said slab forming a mould for retainingcladding metal therein in the molten state whereby, on cooling, saidslab is provided with an integrally bonded layer of cladding metal onsaid end and top surfaces, the lower ends of said channel-shaped endmembers being turned inwardly toward and welded to the bottom surface ofsaid slab. I I

10. Means for producing a composite slab comprising, a slab of basemetal, a pair of relatively thin metal channel-shaped end members weldedto opposite sides of said slab and spacedfrom the end surfaces andprojecting above the-top surface thereof, and a pair of relatively thinmetal side members interfitting with the angles formed by the flangesand beds of said channelshaped members and welded along opposite edgesof the top surface of said slab and to said channel-shaped members, saidend and side members with end and top surfaces of said slab forming 'amould for retaining cladding metal therein in the molten state whereby,on cooling, said slab is provided with integrally bonded layers ofcladding metal on said end and top surfaces.

11, Means for producing a composite slab comprising, a slab of basemetal, a pair of relatively thin metal channel-shaped end members weldedto opposite sides of said slab and spaced from the end surfaces andprojecting above the top surface thereof, and a pair of relatively thinmetal side members interfitting with the angles formed by the flangesand beds of said channel-shaped I members and welded along oppositeedges of the top surface of said slab and to said channelshaped members,said end and side members with end and top surfaces of said slab forminga mould for retaining cladding metal therein in the 'molten statewhereby, on cooling, said slab is provided with integrally bonded layersof cladding metal on said end and top surfaces, the lower ends of saidchannel-shaped end members being turned inwardly toward and welded tothe bottom surfaceof said slab.

12. Means for producing va composite slab comprising, a slab or block ofbase metal of uniform thickness, and a substantially channel-shapedhousing or closure welded to a vertical surface of said slab so as toprovide a vertical mould space of substantially uniform width into whichcladding metal may be introduced to produce a bonding of the claddingmetal to said vertical surface of said slaband which after completion ofsaid cladding operation can be rolled as part of the composite slabformed.

13. Means for producing a composite slab comprising, a slab of basemetal, and a relatively thin metal member welded to opposite verticalsides of said slab so as to form a mould space with the adjacent surfaceof said slab for retaining cladding metal therein in the molten statewhereby, on cooling, said slab is provided with an integrally bondedlayer of cladding metal on said surface, the inner surface of said thinmetal member being lined with a non-bonding material.

14. Means for producing a composite slab comprising, a slab of basemetal, and a relatively thin metal channel-shaped member voided toopposite vertical sides of said slab so as to form a mould space withthe adjacent surface of said slab for retaining cladding metal thereinin the molten state whereby, on cooling, said slab is provided with anintegrally bonded layer of cladding metal on said surface, the innersurface of said thin metal channel-shaped member being linedwith anon-bonding refractory material.

15. The method of producing a composite slab which comprises, welding arelatively thin channel-shaped metal member 'to opposite vertical sidesof a relatively thick slab of base metal to form a vertical mould spacewith the adjacent vertical surface of said. slab, lining the innersurface of the channelshaped mould .member with a non-bonding material,and filling said mould space with cladding metal.

16. The method of producing a composite slab which comprises, welding arelatively thin channel-shaped metal member to opposite vertical sidesof a relatively thick slab of base metal to form a vertical mould spacewith the adjacent vertical surface of said slab, lining the innersurface of the channel-shaped mould member with a non-bondingmateriaLfllling said mould space with cladding metal, allowing thecladding metal to solidify, and removing the mould memher to expose thesurface of the cladding metal.

17. The method of producing a composite slab which comprises, weldingthin metal channelshaped members to opposite vertical sides ,of arelatively thick slab of base metal to form vertical mould spaces withthe adjacent vertical surfaces of said slab, lining the inner surfacesof the channel-shaped mould members with a non-bonding material, andfilling each vertical mould space with a different cladding metal.

7 18. The method of producing a'composite slab which comprises, weldingthin metal channelshaped members to opposite vertical sides of arelatively thick slab of base metal to form vertical mould spaces withthe adjacent vertical surfaces of said slab, lining the inner surfacesof the channel-shaped mould members with a nonbonding material, fillingone vertical mould space with cuprouscladding metal and the othervertical mould space with stainless steel, allowing the cladding metalsto solidify, and removing the mould members to expose the verticalsurfaces of cuprous or stainless steel cladding metals.

THOMAS B. CHACE.

